Portable electronic equipment rack products which may be exposed to extreme environmental conditions such as earthquakes, tremors and the like, must be able to survive and continue to perform. In such locations, the lower surfaces of the rack products are usually physically anchored to the floor. Typically, the racks are also equipped with leveling devices to compensate for floor irregularities and to allow for a plumb installation.
Existing floor anchor and leveling designs comprise two separate systems. After a rack is properly positioned in a floor space, system leveling is achieved by individually adjusting and locking a leveler foot near each corner of the rack. The rack can then be anchored to the floor, typically using a series of anchoring bolts which attach a lower portion of the rack to floor plates that have been previously installed. The anchor bolts are torqued to a high level to keep them in tension during the anticipated earthquake and thus place the levelers in compression.
The preloading on the anchor bolts provides good lateral restraint of the rack due to friction, and eliminates any load fluctuations that might produce loosening or fatigue of the bolts. Unfortunately, the high preload forces, usually several thousand pounds, also require the base of the rack to be very stiff. In addition, if the rack floor stiffness is inadequate and cannot accommodate the bending loads exerted by the floor anchors and levelers, then the required preload cannot be achieved, if at all, without excessive deformation of the rack floor.